Isao Niki

Influence of Amyl Nitrite Inhalation on the Systolic Time Intervals in Normal Subjects and in Patients with Ischemic Heart Disease

The systolic time intervals of the left ventricle in 30 patients with ischemic heart disease but without heart failure were compared with those of 30 normal individuals before and after inhalation of amyl nitrite by using polygraphic recordings.In the normal subjects, following amyl nitrite, the ejection-time index was significantly prolonged, and the pre-ejection period and its index were significantly reduced, while the ejection time was not significantly shortened. The ischemic heart disease group, however, exhibited no significant changes in the ejection-time index, pre-ejection period, or its index, whereas the ejection time was significantly shortened.These differences were not related to heart rate or diastolic blood pressure level but may be explained by a postulated lack of increase in stroke volume or in the contractility of the ischemic myocardium, or both, at the maximal effect of amyl nitrite.The responses of the left ventricular systolic intervals to amyl nitrite may prove useful as a clinical test of latent ventricular functional impairment in subjects with ischemic heart disease.

The clinical usefulness of the amyl nitrite inhalation test in the assessment of the third and atrial heart sounds in ischemic heart disease

Abstract 1. 1. Twenty patients with ischemic heart disease (Group A), 32 with diastolic hypertension (Group B), and 54 normal subjects (Group C) were studied in order to observe the effects of amyl nitrite inhalation on the third and atrial heart sounds. 2. 2. Fifty-five per cent of Group A, 9 per cent of Group B, and 4 per cent of Group C had a significant amplitude increase of these sounds following inhalation of amyl nitrite. 3. 3. It is possible that an increased flow load to the impaired myocardium secondary to a rise in cardiac output and venous return after amyl nitrite inhalation is sufficient to account for the augmentation of the diastolic heart sounds in the majority of the patients in Group A. 4. 4. An initial sudden drop in blood pressure and increase in heart rate may also be responsible for intensification of the diastolic sounds resulting from further coronary insufficiency in the patients with ischemic heart disease. 5. 5. The amyl nitrite inhalation test, with special reference to the diastolic heart sounds, is considered to be a simple and useful clinical procedure for evaluation of myocardial reserve function.